class_docstr: A regular expression-based tokenizer at word boundary.
  This tokenizer default to support MegaMolBART.
  <https://catalog.ngc.nvidia.com/orgs/nvidia/teams/clara/models/megamolbart>
code: def token_to_ids(self, tokens):
      ids_list = []
      for token in tokens:
          ids_list.append(self.vocab.get(token, self._unk_id))
      return ids_list
  
imports: import os
  import re
  from typing import Optional
  import pandas
  from nemo.collections.common.tokenizers.char_tokenizer import TokenizerSpec
  from nemo.utils import logging
label_desc: Use image node_id 7 for calling the RegExTokenizer obj's underlying member method code with example usage: obj.token_to_ids(tokens) and returns: ids_list